Crushed shell substrate

I've been thinking about getting some crushed shells from the beach, boiling them and adding to my substrate or in my filter.

I'm wanting to do this so if my KH levels drop they will dissolve and hold my PH steady. My KH level will soon be a bit over 100, i'm using Seachem's Alkaline Buffer as my tap water is very soft at only 2 dKH. I understand that it will be unlikely for my KH level to drop but would like to have the shells just in case. I've been told some people do this a precaution

I have a 130 litre (34 galon) tank with livebearers and a 50 litre (13 galon) tank with livebearer fry.

What i'd like to know is what amount of crushed shells would be suitable for each tank?

Thanks in advance

 

I answered in your other thread but I'd say 1/2-1 cup for the 34g and 1/4 cup for the 13g. If you're mixing in with substrate then you can't really add too much. Shells and other minerals buffer to 8.2 max generally speaking.

 

I think I might put them in a mesh bag and into the filter of both tanks, still use the same amount of shells?

Just curious, do they buffer to 8.2 max because anything beyond that is too alkaline to dissolve the shells?

 

I actually have no idea....I just know that coral, aragonite, limestone all buffer to 8.2 depending on how much you use. Maybe it just has to do with the amount of carbonates in them.

 

Ok I think i'm just going to leave it for now until I get my GH and KH to where I want it with replenish and alkaline buffer